Chronometer-escapement.



UNITED STATES JOHN W. NUNAll/IAKER,

Patented June 23, 1903.

OF CHICAGO, ILLINOIS.

CHRoNoMET-ER-ESCAPEM ENT.

SPECIFICATION forming part of Letters Patent No. 731,605, datedl' une 23, 1903.

Application tiled February 9, 1903. Serial No. 142,552. (Nogmodel.)

To (t/Z whom, t may concern:

Be it known that I, JOHN W. NUNAMAKER, a citizen of the United States, residingat'Ohicago, in the county of Cook and State ot Illinois, have invented a new and useful Improvement in Chronometer-Escapements, of which the following is a specification. Y,

My invention relates to improvementsl in chronometer-escapements wherein the balance-wheel receives itsimpulses directly from the teeth of the escape-Wheel.

My object is to provide such an escapement of generally improved construction, possessing characteristics which render it particularly simple, strong, durable, and inexpensive to construct and free from all danger of unlocking the escape-wheel at the wrong time.

My object is further to dispense with the delicate auxiliary springs and parts usually provided in escapements of this class. l

In the drawings, Figure l is a broken sec-- tional plan view of so much of the escapement mechanism as is thought necessary to illustrate my invention, the moving parts being shown in one position, wherein theescape-wheel is stopped by the transfer-pallet point, the section being taken on line l in Fig. 3; Fig. 2, a similar view showing the moving parts in the second position, wherein the escape-wheel is stopped by the release-pallet y point; and Fig. 3, a broken sectional view through the bearing-plates, showing my improved escapement mechanism in side elevation.

A is the escape-Wheel of the watch-movement, and a its pinion journaled in the bearing-plates. The escape-wheel is provided with the usual peripheral teeth, which Vmay be of any desired form. Y

B is the balance-Wheel, providedwith the usual hair-spring, (not shown,) and b its staff, journaled in the bearing-plates 002.

Fixed upon the balance-statt vZ1 is a roller C, comprising a disk in two steps of unequal diameter c and d. In the smaller step c is a peripheral recess c', and in the periphery of the larger step d is a notch presenting an impact-shoulder d. On the step d is an eccentric rack-engaging ruby-pin or roller-piu d2 in radial line with the center of the recess c.

D is a balance-lever having the short counterbalanoe-arm D, long arm D2, and fulcrumstaff e, pivoted in the plates m 5c'. On the end of the arm is a headDB, presenting forks preferably formed with notches ff/f2 and with intervening concave recesses g g/, adapted to tit loosely partly around the surface of the step c of the roller, as shown. Fixed to the staff e is a cylindrical rocker E, formed on one side with segmental recess E,'at the opposite edges of which are stops or shoulders h h.

Fis an anchor or anchor-leveren a fulcrumstaff c', journaled in the plates :n x', the lever having the bent long arm F' and short arm F2. At the end of the arm F2 is a shoulder or release pallet-point k, and on the arm F in the position shown is a shoulder or transfer pallet-point la. The free end of the anchor-lever is forked, as shown, to present the shoulders Z. Z', the end between the shoulders being concave in an arc corresponding with the circumference of the rocker E.

Fig. 1 shows'the balance-wheel on its impulse-stroke turning in the direction of the `arrow just after the impact-shoulder d has been struck and released by the tooth m of the escape-wheel in the usual manner. The ruby-pin d2 has just passed out of engagement with the notch f, leaving the lever D in the position wherein the shoulder h engages the shoulder Z thereon to hold the transfer-pallet 7c in the path of the tooth m of' the escapewheel to stop the latter.` I prefer to provide a balance-wheel having along angular stroke on account of the increased accuracy of its control upon the escapement mechanism thereby affected, and While it is usual in watch-movements to provide balance-wheeloperating mechanism which turns the balance-wheel normally but a half-revolution or less, or at most a three-quarter revolution, in veach direction I provide, for the reason stated,

balance wheel operatin g mechanism which causes the balance-wheel 4to turn normally about a full revolution in each direction from the point of impact with each impulse. In escapements as hithertoprovided it hasbeen considered unsafe to permit so great a normal stroke of the balance-wheel, because of the danger when the balance-wheel is given an undue impulse, as w-hen the watch is shaken, ot' the pallets unlocking a second IOO time in a chronometer-watch or the jewelis striking an obstruction, such as the back of the lever in a lever-watch, and thus increasing the time by rebounding or breaking the jewel. In my improved construction these dangers are overcome. In its further movement on the impulse-stroke from the position shown in Fig. l the rubypin d2 when it reaches the notch f will enter the latter and swing the lever on its fulcrum, turning the shoulder h farther beneath the shoulder Z. This turning of the lever may continue under any undue influence against the balancewheel until the notch f reaches the position of the notchf in Fig. l. In the return stroke of the balance-wheel the ruby-pin d2 enters the socketf' and in turning in the direction indicated bythe arrow in Fig. 2 moves the lever D from the position shown in Fig. l to that shown in Fig. 2. This movement of the lever D turns the shoulder h out of engagement with the shoulder l, thus releasing the anchor-lever and permitting it to be swung by pressure of the tooth m against the pallet-point 7c to release said tooth, the shoulder portion Z moving in the recess E and the pallet-point 7c moving into the path of the escape-wheel tooth m2 to engage and stop the same. This engagement causes the shoulder l' to be pressed against the shoulder h. The base of the recess E presents a convex impact-surface E2 for the shoulders Z Z to strike against, and thus prevent their passing the centerline of the rocker and becomingwedged. In the further turning of the balance-wheel from the position shown in Fig. 2 in the direction of the arrow in that figure the rubypin d2 may enter the notch f2 and underany undue influence against the balance-wheel swing the lever to the position wherein the said notch is in the position ofthe notch f in Fig. 2, returning the lever in its reverse movement and releasing it at the position thereof shown, then rengaging the notch f in its further movement and releasing said notch when the impact-face d is struck by the next tooth m3 of the escape-wheel. Thus it will be seen that the balance-wheel is free to turn approximately two full revolutions in each direction from the impulse-point, which is in excess of any ordinary requirements, even when the movement is violently shaken. The recesses g g by their engagement with the step c of the roller prevent any displacement of the lever while the ruby-pin d2 is out of engagement therewith.

Myimproved escapement employs comparatively few parts, all of which are of particularly simple, strong, and inexpensive construction. The anchor is simply a lock for the escape-wheel and does not operate against the balance-wheel, as in lever-watches. The

pallet-points presentinclined shoulders to the escape-wheel teeth to be moved by pressure thereof to swing the anchor when its shoulders are out of engagement with the they may be variously modified in the matter of details of construction Without departing from the spirit of myinvention as defined by the claims.

What I claim as new, and desire to secure by Letters Patent, is-

l. In a chronometer-escapement, the combination with a toothed escape-wheel, and balance-wheel in the path thereof, of a fulcrumed anchor-lever provided with pallets, at opposite sides of its fulcrum, and with pallet-locking shoulders, a balance-lever having shoulders movable to engage and release said pallet-locking shoulders, forks on said lever and a ruby-pin on said balance-wheel.

2. Ina chronometer-escapement, the combination with a toothed escapewheel, and balance-wheel in the path thereof, of a ful'- crumed anchor-lever providedwith inclined pallets at opposite sides of its fulcrum to be moved by pressure against them of the escape-wheel teeth, and provided with palletlocking shoulders, a balance-lever having shoulders movable to engage and release said pallet-locking shoulders, forks on said lever and a ruby-pin on said balance-wheel.

3.Y In a chronometer-escapement, the comv bination with the toothed escape-wheel and balance-wheel in the path thereof, of a fulcrumed anchor-lever provided with pallets, at opposite sides of its fulcrum, and with pallet-locking shoulders at one end, a fulcrumed balance-lever having shoulders movable to engage and release said pallet-locking shoulders, forks on said lever and a ruby-pin on said balance-wheel.

4. In a chronometer-escapement, the combination with the toothed escape-wheel and4 balance-wheel in the path thereof, of a fulcrumed balance-lever, a rocker on said lever near its fulcrum, having pallet-locking shoul- IIO ders and a recess between said shoulders, an

anchor fulcrumed between its ends, having pallets on opposite sides of its fulcrum, and a recess at one end, fitting slidingly against said rocker, flanked by pallet-locking shoulders adapted to enter the said recess in, and engage'the shoulders on, said rocker in their movement, forks on said balance-lever, and a rubypin on said balance-wheel, substantially as and for the purpose set forth.

5. In a chronometer-escapement, the combination with the toothed escape-wheel and balance-wheel in the path thereof, o'f a fulcrumed balance-lever, a rocker on said lever as and for the purpose set forth.

6. In a chrononieter-escapement, the cornbination with the toothed escape-wheel and balance-wheel in the path thereof, of a fulcrumed anchor provided with pallets at opposite sides of its fulcrum and with palletlocking shoulders, a balance-lever having shoulders and movable to engage and release therewith said pallet-locking shoulders, forks on said lever presenting three ruby-pin-engaging notches, and a ruby-pin on said balance-wheel, substantially as and for the purpose set forth.

7. In a chronometer-escapement, the cornbination with an escape-wheel and balancewheel, of a fulcrumed anchor provided with pallets at opposite sides of its fulcruin, and with pallet-locking shoulders, a balance-lever having shoulders and movable to engage and release therewith said pallet-lockingshoulders, a roller on the balance-wheel provided with an impact-face, in the path of the escapewheel, and with a ruby-pin, and forks on said lever presenting three engaging notches for the said ruby-pin with intermediate engaging recesses for said roller, substantially as and for the purpose set forth.

JOHN W. NUNAMAKER.

In presence of WALTER WINBERG, WM. B. DAvIEs. 

